Technical Field
The present disclosure relates to films/coatings (e.g., transparent conductive films/coatings) and methods for fabricating films/coatings and, more particularly, to methods for fabricating transparent conductive films by trapping at least a portion of a layered material (e.g., graphene sheet(s) or layer(s) of graphite) at an interface of a phase separated system (e.g., at an interface of two non-mixing solvents).
Background Art
In general, current attempts to use graphene for some applications (e.g., graphene film applications) involve the use of oxidized graphene (GO—graphene oxide), followed by a thermal reduction between about 400° C. and about 1000° C. Moreover, some currently used transparent conductive coatings typically employ indium tin oxide (ITO), a rare, expensive and brittle material.
In general, graphite's lack of solubility is an obstacle to its utilization, and is sometimes attempted to be overcome by oxidizing and sonicating the graphite to obtain aqueous suspensions, followed by reduction after processing. However, the oxidation and reduction process significantly degrades the properties of the graphene. See, e.g., U.S. Pat. Nos. 7,824,651 and 7,449,133, the entire contents of each being hereby incorporated by reference in their entireties.
For example, the lack of graphene solubility has necessitated the use of graphene oxide (GO), reduced GO (rGO) or chemical vapor deposition (CVD) sources, rather than pristine, naturally derived graphene to produce transparent conducting films. (See, e.g., D. S. Hecht, L. Hu, G. Irvin, Advanced Materials, (2011)).
While the production of CVD grown graphene sheets with large lateral dimensions has been demonstrated, the cost of this process generally limits the possible applications. (See, e.g., X. Li et al., Journal of the American Chemical Society 133, 2816 (Apr. 9, 2011); and J. W. Suk et al., ACS Nano 5, 6916 (Sep. 27, 2011)). The use of rGO is sometimes reported, despite the fact that rGO's electrical conductivity is about one to two orders of magnitude less than that of graphene (C. Gómez-Navarro et al., Nano Letters 10, 1144 (May 14, 2010)). Moreover, reports of graphitic films also discuss the use of GO layered with conducting polymers, and films of temperature treated GO (See, e.g., S. H. Domingues at al., Chemical Communications 47, 2592 (2011); and F. J. Toelle et al., Advanced Functional Materials 22, 1136 (2012)).
Thus, an interest exists for improved films/coatings (e.g., transparent conductive films/coatings), and related methods for fabricating improved films/coatings. These and other inefficiencies and opportunities for improvement are addressed and/or overcome by the assemblies, systems and methods of the present disclosure.